app/common/common.py

   1 import os
   2 import re
   3 import json
   4 import base64
   5 import sqlite3
   6 import requests
   7 import hmac, hashlib
   8 import requests_cache
   9 import dateutil.parser
  10 from xml.etree import ElementTree
  11 from configparser import ConfigParser
  12 from datetime import datetime, timezone
  13 from urllib.parse import parse_qs, urlparse
  14
  15 cf = ConfigParser()
  16 config_filename = os.environ.get('YT_CONFIG', '/etc/yt/config.ini')
  17 cf.read(config_filename)
  18 if not 'global' in cf: # todo: full config check
  19     raise Exception("Configuration file not found or empty")
  20
  21 # Note: currently expiring after 10 minutes. googlevideo-urls are valid for 5h59m, but this makes reddit very stale and premiere videos won't start.  TODO: exipre when video is livestream/premiere/etc
  22 requests_cache.install_cache(backend='memory', expire_after=10*60, allowable_codes=(200,), allowable_methods=('GET', 'HEAD', 'POST'))
  23
  24 # Note: requests-cache doesn't use redis expiry, so we need this in all backends:
  25 # https://github.com/reclosedev/requests-cache/issues/58#issuecomment-164537971
  26 # TODO: only run for long-running processes, i.e. the frontend
  27 from threading import Timer
  28 def purge_cache(sec):
  29     requests_cache.remove_expired_responses()
  30     t = Timer(sec, purge_cache, args=(sec,))
  31     t.setDaemon(True)
  32     t.start()
  33 purge_cache(10*60)
  34
  35 # for debugging purposes, monkey patch requests session to store each requests-request in a flask-request's g object (url and response). we can then use a flask error_handler to include the request data in the error log.
  36 # since we also call config from outside the flask appcontext, it is wrapped in a try-catch block.
  37 from flask import g
  38 import requests
  39 from requests import Session as OriginalSession
  40 class _NSASession(OriginalSession):
  41     def request(self, method, url, params=None, data=None, **kwargs):
  42         response = super(_NSASession, self).request(
  43             method, url, params, data, **kwargs
  44             )
  45         try:
  46             if 'api_requests' not in g:
  47                 g.api_requests = []
  48             g.api_requests.append((url, params, response.text))
  49         except RuntimeError: pass # not within flask (e.g. utils.py)
  50         return response
  51 requests.Session = requests.sessions.Session = _NSASession
  52
  53 def fetch_xml(feed_type, feed_id):
  54     # TODO: handle requests.exceptions.ConnectionError
  55     r = requests.get("https://www.youtube.com/feeds/videos.xml", {
  56         feed_type: feed_id,
  57     })
  58     if not r.ok:
  59         return None
  60
  61     return r.content
  62
  63 def parse_xml(xmldata):
  64     ns = {
  65         'atom':"http://www.w3.org/2005/Atom",
  66         'yt': "http://www.youtube.com/xml/schemas/2015",
  67         'media':"http://search.yahoo.com/mrss/",
  68         'at': "http://purl.org/atompub/tombstones/1.0",
  69     }
  70
  71     feed = ElementTree.fromstring(xmldata)
  72
  73     if feed.find('at:deleted-entry',ns):
  74         (_,_,vid) = feed.find('at:deleted-entry',ns).get('ref').rpartition(':')
  75         return None, None, [{'deleted': True, 'video_id': vid}], None, None
  76
  77     title = feed.find('atom:title',ns).text
  78     author = feed.find('atom:author/atom:name',ns).text \
  79         if feed.find('atom:author',ns) else None
  80     # for /user/<> endpoint: find out UC-id:
  81     # for playlists: this is who created the playlist:
  82     try:   channel_id = feed.find('yt:channelId',ns).text
  83     except:channel_id=None # XXX: why does ternary not work!?
  84     # for pullsub: if this exists, we're looking at a playlist:
  85     try:   playlist_id = feed.find('yt:playlistId',ns).text
  86     except:playlist_id=None # XXX: why does ternary not work!?
  87     videos = []
  88     for entry in feed.findall('atom:entry',ns):
  89         videos.append({
  90             'video_id': entry.find('yt:videoId',ns).text,
  91             'title': entry.find('atom:title',ns).text,
  92             'published': entry.find('atom:published',ns).text,
  93             'channel_id': entry.find('yt:channelId',ns).text,
  94             'author': entry.find('atom:author',ns).find('atom:name',ns).text,
  95             # extra fields for pull_subs/webhook:
  96             'updated': entry.find('atom:updated',ns).text,
  97         })
  98
  99     return title, author, videos, channel_id, playlist_id
 100
 101 def update_channel(db, xmldata, from_webhook=False):
 102     if not xmldata: return False
 103
 104     # Note: websub does not return global author, hence taking from first video
 105     title, author, videos, channel, playlist = parse_xml(xmldata)
 106
 107     c = db.cursor()
 108     for i, video in enumerate(videos):
 109         if video.get('deleted'):
 110             # Note: Deletion events are not just fired for actual deletions,
 111             # but also for unlisting videos and livestreams that just ended
 112             # (even postLiveDVR ones). Hence, we don't follow it.
 113             flask_logger(f"ignoring deleted/unlisted/ended video/stream {video['video_id']}")
 114             break
 115
 116         c.execute("SELECT 1 FROM videos WHERE id=?",(video['video_id'],))
 117         new_video = len(c.fetchall()) < 1
 118         if new_video:
 119             flask_logger(f"new video {video['video_id']}")
 120             _, _, meta, _, _ = get_video_info(video['video_id'])
 121             # The 'published' timestamp sent in websub POSTs are often wrong (e.g.:
 122             # video gets uploaded as unlisted on day A and set to public on day B;
 123             # the webhook is sent on day B, but 'published' says A. The video
 124             # therefore looks like it's just an update to an older video).
 125             # g_v_i gives is the date the video was published to viewers, so we
 126             # prefer that. But since g_v_i only returns the date without time,
 127             # we still use xmlfeed's date if it's the same date.
 128             published = dateutil.parser.parse(video['published'])
 129             length = None
 130             livestream = None
 131             if meta:
 132                 meta = video_metadata(meta)
 133                 published2 = dateutil.parser.parse(meta['published'])
 134                 flask_logger(f"published {published} / {published2}")
 135                 if published < published2: # g_v_i date is more accurate:
 136                     published = published2
 137                 length = meta['length']
 138                 livestream = meta['livestream']
 139
 140             now = datetime.now(timezone.utc)
 141
 142             # we pretend that all videos uploaded this week were uploaded just
 143             # now, so the user sees it at the top of the feed, and it doesn't
 144             # get inserted somewhere further down.
 145             if (now - published).days < 7:
 146                 timestamp = now
 147             else:#, it's just an update to an older video.
 148                 timestamp = published
 149
 150             c.execute("""
 151                 INSERT OR IGNORE INTO videos
 152                     (id, channel_id, title, length, livestream, published, crawled)
 153                 VALUES (?, ?, ?, ?, ?, datetime(?), datetime(?))
 154             """, (
 155                 video['video_id'],
 156                 video['channel_id'],
 157                 video['title'],
 158                 length,
 159                 livestream,
 160                 video['published'],
 161                 timestamp
 162             ))
 163         else:
 164             # update video title (everything else can't change)
 165             c.execute("""
 166                 UPDATE OR IGNORE videos
 167                     SET title = ?
 168                     WHERE id = ?
 169             """, (
 170                 video['title'],
 171                 video['video_id'],
 172             ))
 173
 174         # for channels, this is obviously always the same, but playlists can
 175         # consist of videos from different channels:
 176         if i == 0 or playlist:
 177             c.execute("""
 178                 INSERT OR REPLACE INTO channels (id, name)
 179                                 VALUES (?, ?)
 180             """, (video['channel_id'], video['author']))
 181
 182         # keep track of which videos are in a playlist, so we can show the user
 183         # why a video is in their feed:
 184         if playlist:
 185             c.execute("""
 186                 INSERT OR IGNORE INTO playlist_videos (video_id, playlist_id)
 187                                VALUES (?, ?)
 188             """, (video['video_id'], playlist))
 189
 190     if playlist and not from_webhook: # Note: playlists can't get updated via websub
 191         c.execute("""
 192             INSERT OR REPLACE INTO playlists (id, name, author)
 193                             VALUES (?, ?, ?)
 194             """, (playlist, title, channel))
 195         c.execute("""
 196             INSERT OR REPLACE INTO channels (id, name)
 197                             VALUES (?, ?)
 198         """, (channel, author))
 199
 200     db.commit()
 201
 202     return True
 203
 204 def get_video_info(video_id, sts=0, algo=""):
 205     """
 206     returns: best-quality muxed video stream, stream map, player_response, error-type/mesage
 207     error types: player, malformed, livestream, geolocked, exhausted
 208     """
 209     player_error, metadata = None, None # for 'exhausted'
 210     with sqlite3.connect(cf['global']['database']) as conn:
 211         c = conn.cursor()
 212         c.execute("SELECT * FROM captcha_cookies")
 213         cookies = dict(c.fetchall())
 214     for el in ['WEB_EMBEDDED_PLAYER', 'WEB']: # sometimes, only one or the other works
 215         today = datetime.now(timezone.utc).strftime("%Y%m%d")
 216         # XXX: anticaptcha hasn't been adapted
 217         # XXX: this is not cached any more!
 218         r = requests.post("https://www.youtube-nocookie.com/youtubei/v1/player?key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8", json={
 219             'videoId': video_id,
 220             'context': {
 221                 'client': {
 222                     'gl': 'US',
 223                     'hl': 'en',
 224                     'clientName': el,
 225                     'clientVersion': f'2.{today}.01.01',
 226                 }
 227             },
 228             'playbackContext': {'contentPlaybackContext': {'signatureTimestamp': sts}}
 229         }, cookies=cookies)
 230
 231         if r.status_code == 429:
 232             return None, None, None, 'banned', 'possible IP ban'
 233
 234         metadata = r.json()
 235         playabilityStatus = metadata['playabilityStatus']['status']
 236         if playabilityStatus != "OK":
 237             playabilityReason = metadata['playabilityStatus'].get('reason',
 238                     '//'.join(metadata['playabilityStatus'].get('messages',[])))
 239             player_error = f"{playabilityStatus}: {playabilityReason}"
 240             if playabilityStatus == "UNPLAYABLE":
 241                 continue  # try again with next el value (or fail as exhausted)
 242             # without videoDetails, there's only the error message
 243             maybe_metadata = metadata if 'videoDetails' in metadata else None
 244             return None, None, maybe_metadata, 'player', player_error
 245
 246         # livestreams have no adaptive/muxed formats:
 247         is_live = metadata['videoDetails'].get('isLive', False)
 248
 249         if not 'formats' in metadata['streamingData'] and not is_live:
 250             continue # no urls
 251
 252         formats = metadata['streamingData'].get('formats',[])
 253         for (i,v) in enumerate(formats):
 254             if not ('cipher' in v or 'signatureCipher' in v): continue
 255             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 256             formats[i]['url'] = unscramble(cipher, algo)
 257
 258         adaptive = metadata['streamingData'].get('adaptiveFormats',[])
 259         for (i,v) in enumerate(adaptive):
 260             if not ('cipher' in v or 'signatureCipher' in v): continue
 261             cipher = parse_qs(v.get('cipher') or v.get('signatureCipher'))
 262             adaptive[i]['url'] = unscramble(cipher, algo)
 263
 264         stream_map = {
 265             'adaptive': adaptive, 'muxed': formats,
 266             'hlsManifestUrl': metadata['streamingData'].get('hlsManifestUrl'),
 267         }
 268
 269         url = sorted(formats, key=lambda k: k['height'], reverse=True)[0]['url'] \
 270             if not is_live else None
 271
 272         # ip-locked videos can be recovered if the proxy module is loaded:
 273         is_geolocked = 'gcr' in parse_qs(urlparse(url).query)
 274
 275         nonfatal = 'livestream' if is_live \
 276             else 'geolocked' if is_geolocked \
 277             else None
 278
 279         return url, stream_map, metadata, nonfatal, None
 280     else:
 281         return None, None, metadata, 'exhausted', player_error
 282
 283 def unscramble(cipher, algo):
 284     signature = list(cipher['s'][0])
 285     for c in algo.split():
 286         op, ix = re.match(r"([rsw])(\d+)?", c).groups()
 287         ix = int(ix) % len(signature) if ix else 0
 288         if op == 'r': signature = list(reversed(signature))
 289         if op == 's': signature = signature[ix:]
 290         if op == 'w': signature[0], signature[ix] = signature[ix], signature[0]
 291     sp = cipher.get('sp', ['signature'])[0]
 292     sig = cipher.get('sig', [''.join(signature)])[0]
 293     return f"{cipher['url'][0]}&{sp}={sig}"
 294
 295 def video_metadata(metadata):
 296     if not metadata:
 297         return {}
 298
 299     meta1 = metadata['videoDetails']
 300     meta2 = metadata['microformat']['playerMicroformatRenderer']
 301
 302     # sometimes, we receive the notification so early that the length is not
 303     # yet populated. Nothing we can do about it.
 304     length = int(meta2['lengthSeconds']) or int(meta1['lengthSeconds']) or None
 305
 306     published_at = meta2.get('liveBroadcastDetails',{}) \
 307         .get('startTimestamp', f"{meta2['publishDate']}T00:00:00Z")
 308
 309     # Note: 'premiere' videos have livestream=False and published= will be the
 310     # start of the premiere.
 311     return {
 312         'title': meta1['title'],
 313         'author': meta1['author'],
 314         'channel_id': meta1['channelId'],
 315         'published': published_at,
 316         'views': int(meta1['viewCount']),
 317         'length': length,
 318         'livestream': meta1['isLiveContent'],
 319     }
 320
 321 def store_video_metadata(video_id):
 322     # check if we know about it, and if not, fetch and store video metadata
 323     with sqlite3.connect(cf['global']['database']) as conn:
 324         c = conn.cursor()
 325         c.execute("SELECT 1 from videos where id = ?", (video_id,))
 326         new_video = len(c.fetchall()) < 1
 327         if new_video:
 328             _, _, meta, _, _ = get_video_info(video_id)
 329             if meta:
 330                 meta = video_metadata(meta)
 331                 c.execute("""
 332                     INSERT OR IGNORE INTO videos (id, channel_id, title, length, published, crawled)
 333                                    VALUES (?, ?, ?, ?, datetime(?), datetime(?))
 334                 """, (
 335                     video_id,
 336                     meta['channel_id'],
 337                     meta['title'],
 338                     meta['length'],
 339                     meta['published'],
 340                     meta['published'],
 341                 ))
 342                 c.execute("""
 343                     INSERT OR REPLACE INTO channels (id, name)
 344                                     VALUES (?, ?)
 345                 """, (meta['channel_id'], meta['author']))
 346
 347 def fetch_video_flags(token, video_ids):
 348     with sqlite3.connect(cf['global']['database']) as conn:
 349         c = conn.cursor()
 350         c.execute("""
 351             SELECT video_id,display
 352               FROM flags
 353              WHERE user = ?
 354                AND display IS NOT NULL
 355                AND video_id IN ({})
 356                -- AND display = 'pinned'
 357         """.format(",".join(["?"]*len(video_ids))), (token,*video_ids))
 358         flags = c.fetchall()
 359         pinned = [video for video,disp in flags if disp == 'pinned']
 360         hidden = [video for video,disp in flags if disp == 'hidden']
 361
 362         return pinned, hidden
 363
 364 from werkzeug.exceptions import NotFound
 365 class NoFallbackException(NotFound): pass
 366 def fallback_route(*args, **kwargs): # TODO: worthy as a flask-extension?
 367     """
 368     finds the next route that matches the current url rule, and executes it.
 369     args, kwargs: pass all arguments of the current route
 370     """
 371     from flask import current_app, request, g
 372
 373     # build a list of endpoints that match the current request's url rule:
 374     matching = [
 375         rule.endpoint
 376         for rule in current_app.url_map.iter_rules()
 377         if rule.rule == request.url_rule.rule
 378     ]
 379     current = matching.index(request.endpoint)
 380
 381     # since we can't change request.endpoint, we always get the original
 382     # endpoint back. so for repeated fall throughs, we use the g object to
 383     # increment how often we want to fall through.
 384     if not '_fallback_next' in g:
 385         g._fallback_next = 0
 386     g._fallback_next += 1
 387
 388     next_ep = current + g._fallback_next
 389
 390     if next_ep < len(matching):
 391         return current_app.view_functions[matching[next_ep]](*args, **kwargs)
 392     else:
 393         raise NoFallbackException
 394
 395 def websub_url_hmac(key, feed_id, timestamp, nonce):
 396     """ generate sha1 hmac, as required by websub/pubsubhubbub """
 397     sig_input = f"{feed_id}:{timestamp}:{nonce}".encode('ascii')
 398     return hmac.new(key.encode('ascii'), sig_input, hashlib.sha1).hexdigest()
 399
 400 def websub_body_hmac(key, body):
 401     return hmac.new(key.encode('ascii'), body, hashlib.sha1).hexdigest()
 402
 403 def flask_logger(msg, level="warning"):
 404     level = dict(
 405         CRITICAL=50,
 406         ERROR=40,
 407         WARNING=30,
 408         INFO=20,
 409         DEBUG=10,
 410         NOTSET=0,
 411     ).get(level.upper(), 0)
 412     try:
 413         from flask import current_app
 414         current_app.logger.log(level, msg)
 415     except:
 416         pass
 417
 418 def pp(*args):
 419     from pprint import pprint
 420     import sys, codecs
 421     pprint(args, stream=codecs.getwriter("utf-8")(sys.stderr.buffer))